WOE IS US
Running Dry

Neither picturesque like rivers nor recreational like lakes, aquifers keep a low profile. Without them, though, we'd be both thirsty and hungry. Half of all U.S. drinking water is groundwater, and many of the fields that grow our food rely on it for irrigation.
But as populations grow, water that's been chilling underground since the end of the last Ice Age is being sucked up faster than cold lemonade on a hot day.

"The water accumulated over a long period of time," says Jay Famiglietti, director of the University of California Center for Hydrologic Modeling. "It was colder and, in some places, wetter, so there was a lot of glacial melt that was recharging these aquifers. That's all disappeared, and now many of those regions are very, very dry. What we take out doesn't come back."

The Ogallala Aquifer, which stretches from the Texas-New Mexico border to the edge of South Dakota, is heavily depleted. A recent study published in the Proceedings of the National Academy of Sciences found that much of the southern High Plains—the nation's breadbasket—may be unable to irrigate crops within 30 years.

California's Central Valley, the source of much of the country's fruits and vegetables, is also running dry. In the six-year stretch ending in 2010, farmers there drained nearly enough groundwater to fill Lake Mead, the nation's largest reservoir. As more water is used, what remains becomes harder to get and of poorer quality.

"We're seeing groundwater being depleted at a very rapid clip in arid and semiarid regions," Famiglietti says. "If we don't take steps now, we will not be able to sustain a water supply in the future." —Dashka Slater